1) Field of the Invention
The present invention relates generally to agricultural implements and, more specifically, to structure for clearing trash from a narrow area ahead of an opener or similar earthworking tool and for preventing hairpinning of trash around the opener.
2) Related Art
During planting operations, residue such as wheat straw or corn stalks is often encountered by the furrow opening device on the seeding implement. If the soil is soft or the residue is very tough, much residue is pushed into the seed trench. The residue prevents seed from contacting soil and reduces the opportunity for seed germination and healthy initial plant growth. Long pieces of trash can hairpin around the opener and cause poor operation.
Devices are available such as the type which include a pair of spoked wheels operating on substantially horizontal axles and steered relative to the forward direction so the spokes nearly touch or interlock. The point of closest proximity of the spokes, often referred to as the pinch point, is in the plane formed by the steered axles and is nearly one wheel radius above the soil surface. The amount of engagement of the spokes with the soil reduces this distance above the soil, and the spokes are separated at the point of soil entry to leave an uncleaned strip of ground. The uncleaned strip can be narrowed by increasing the operating depth, but increasing depth can cause excessive soil removal from the area. Other devices having a large wheel with narrow spokes permit excessively deep operation and soil displacement.
Mounting a cleaning device in the limited space available adjacent an opener has been a source of several problems. Fixed cleaning arrangements which are connected directly to the opener assembly or frame without provision for independent movement are subject to damage if obstacles or other large ground surface irregularities are encountered, and the location of the cleaning device relative to the opener can change detrimentally as the opener follows the ground contour. Pivoting arrangements often fail to track well, and if the cleaning wheel structure is supported closely adjacent the disk opener, the structure can actually hit the opener. Moving the cleaning structure farther ahead of the wheel to avoid interference requires more room than often is available, and as the cleaning wheels are moved ahead there is less stretching and holding of the trash close to the soil entry point of the disk so trash hairpins more easily at the disk edge. Supporting the cleaning device in a limited space and providing effective operation without nose-diving or bulldozing of soil during operation have continued to present problems.